Fix setting array length to be ES5 conform.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 3187467b380a9cde1d4355ea007238fb1075e317..5836ed633f3d01429b48540cd0f49cfe84eebed3 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2987,9 +2987,6 @@ class NumberDictionary: public Dictionary<NumberDictionaryShape, uint32_t> {
   // requires_slow_elements returns false.
   inline uint32_t max_number_key();
 
-  // Remove all entries were key is a number and (from <= key && key < to).
-  void RemoveNumberEntries(uint32_t from, uint32_t to);
-
   // Bit masks.
   static const int kRequiresSlowElementsMask = 1;
   static const int kRequiresSlowElementsTagSize = 1;